(a) Field of the Invention
The present invention relates to a gas capture plant that is applicable to a gas-liquid separating process and more particularly, to a gas capture plant that produces rich absorbent liquid by dissolving the object gas in an absorbent liquid, regenerating the produced rich absorbent liquid to generate regeneration gas, and then separating the target gas from the regeneration gas by condensing the regeneration gas.
(b) Description of the Related Art
Recently, techniques for suppressing the release of carbon dioxide into the atmosphere have been researched and developed as global warming and air pollution become increasingly severe. For example, an increased focus has been placed on developing a method of efficiently trapping carbon dioxide emitted from thermoelectric power plants or boiler equipment. Among the various methods of trapping gas, the chemical absorption method using an absorbent liquid is particularly suitable for trapping a substantial capacity of carbon dioxide. A gas capture plant using the chemical absorption method, absorbs the carbon dioxide emitted from thermoelectric power plants or boiler equipment into an absorbent liquid within an absorption tower. Thereafter, the regeneration tower heats the saturated absorbent liquid containing carbon dioxide separating the regeneration gas containing the carbon dioxide from the absorbent liquid.
Typically, a conventional gas capture plant mixes the carbon dioxide and the absorbent liquid at a rectifier mounted in the absorption tower. An apparatus for capturing the absorbent liquid at a center portion of the rectifier is mounted in a filler or a separating plate to evenly separate the gas. Furthermore, the filler is mounted in an upper portion of the absorption tower preventing channeling from occurring when the absorbent liquid passes through the filler in the rectifier. In other words, changing a structure of the upper portion of the absorption tower prevents channeling of the gas and the liquid. However, controlling the abnormal phenomena due to the rapid linear velocity of gas at the lower portion of the absorption tower and an absorbent liquid drop has proven to be difficult.
Additionally, a reboiler for heating the absorbent liquid and serving as an energy source for regeneration is mounted to the regeneration tower. The reboiler heats the absorbent liquid to a suitable temperature for regeneration to separate the gas contained in the absorbent liquid. The gas separated from the absorbent liquid flows to an upper portion of the regeneration tower to capture the useful material into a condenser and to discharge the gas from the regeneration tower. Conventionally, a kettle type or a thermocyphon type reboiler have been used. The kettle type reboiler includes first and second parts disposed therein and divided by a wall. A heater or a heat-exchanger is disposed in the first part and an absorbent liquid outlet is formed at the second part. When the absorbent liquid containing the gas is supplied to an upper portion of the reboiler, a level of the absorbent liquid in the reboiler increases. Then, the heater or the heat-exchanger increases the temperature of the absorbent liquid and the gas is separated from the absorbent liquid and dissipates. As the absorbent liquid is continuously supplied, the gas is removed or reduced and is thereby transported via the wall into the second part. Thereafter, the absorbent liquid is discharged from the reboiler through the absorbent liquid outlet. Often a fluid oscillation (e.g., wave, liquid movement or fluid disturbance) occurs within the reboiler of the kettle type, due to the movement generated by the liquid drop and the boiling of the mixed liquid. Therefore, it may be difficult to precisely control the level of the absorbent liquid.
The reboiler of the thermocyphon type includes a heater or a heat-exchanger disposed therein and an absorbent liquid outlet formed at a bottom surface of the reboiler. When the absorbent liquid containing the gas is supplied to an upper portion of the reboiler, the absorbent liquid in the reboiler is heated by the heater or the heat-exchanger. The gas is separated from the absorbent liquid and dissipates in an upward direction. The absorbent liquid from which the gas is removed or flows in the direction of the bottom surface of the reboiler and is discharged from the reboiler through the absorbent liquid outlet. The level of the absorbent liquid may be difficult to control in the reboiler of the thermocyphon type, due to boiling. Additionally, since the boiler is constructed without a wall, the mixed liquid remains in the reboiler for a minimal short duration of time. Therefore, a reduced amount of energy is supplied to the mixed liquid which reduces the efficiency of the gas separation for regeneration.
The kettle type and the thermocyphon type reboilers have a similar supply path of the mixed liquids and a discharge path of the gases separated from the mixed liquids. Therefore, when bubbles are generated due to heating, the mixed liquid cannot reach the heater or the heat-exchanger since the path is obstructed by the bubbles. When this condition continues, the level of the mixed liquid in the regeneration tower is elevated thereby impeding the intended function of the absorption tower and the regeneration tower.
Furthermore, a gas capture plant using the chemical absorption method includes a condenser configured to condense the regeneration gas and generate condensate, and a reflux apparatus configured to discharge the gas evaporated from the condensate to an exterior thereof to capture the gas and supply the condensate back into the regeneration tower. Typically, within a conventional gas capture plant, the condenser and the reflux apparatus are separately disposed to adjust the level of the condensate within the reflux apparatus. As a result, the volume of the gas capture plant increases and a larger space is required to mount the gas capture plant. Additionally, a substantial amount of heat loss occurs between the reflux apparatus and the condenser since the reflux apparatus and the condenser are separate.
The above information disclosed in this section is merely for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.